Houstonians make Forbes' world's billionaires list

March 5, 2013

Nick de la Torre/Houston Chronicle

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George P. Mitchell, 92, has been called the father of natural gas shale drilling. He was the first utilize horizontal drilling and hydraulic fracking to break open rock formations in Texas. He is worth an estimated $2 billion.

Nick de la Torre/Houston Chronicle

8of18

George P. Mitchell, 92, has been called the father of natural gas shale drilling. He was the first utilize horizontal drilling and hydraulic fracking to break open rock formations in Texas. He is worth an estimated $2 billion.